UNIT 2

• OMR (optical mark reader) is able to read marks written in pen/pencil.
• OCR (optical character reader) scans text from hardcopies and converts it into an editable form which can be used and edited in range of software e.g. word processors
• Acutators are sent digital signals by computer to affect or control real world
• OMR ADVS: fast method of inputting data, less chance of errors, more accurate than OCR
• OMR DISADVS: forms must be completed correctly
• OCR ADVS: faster method of data entry, less chance of errors
• OCR DISADVS: barcode can be unreadable, could be swapped, expensive system
• DOT MATRIX PRINTERS ADVS: not affected by hot/dusty environments, can print carbon copies and cheap to run and maintain
• DOT MATRIX PRINTERS DISADVS: slow printing, poor quality printing and noisy
• 3D PRINTERS ADVS: products printed can be customised, protypes can be created quickly, parts can be created which are no longer manufactured and artificial organs can be printed
• 3D PRINTERS DISADVS: counterfeit and dangerous products could be made, expensive
• LASER PRINTERS ADVS: high quality printing, quick printing, toner lasts longer than inkjet cartridges and print quietly
• LASER PRINTERS DISADVS: expensive
• A sensor is a device that converts a real world property into data that computer can process
• You can have sensors for temp, light, moisture, water-level, proximity, movement and pressure
• INKJET PRINTERS ADVS: cheaper than laser printers, small in size, high quality printing
• INKJET PRINTERS DISADVS: ink cartridge can run out quickly and slow printing time
• CATHODE RAY TUBE (CRT) MONITORS ADVS: cheaper than other monitors, can be used with light pens, good resolution
• CATHODE RAY TUBE (CRT) MONITORS DISADVS: big in size and safety hazard if not correctly supported
• LCD MONITORS ADVS: smaller and lighter so less desk space required and consume less power
• LCD MONITORS DISADVS: resolution not as good as CRT
• LEDs ADVS: produce better light improving color definition, can be used in different types of light, energy efficient, last long time
• LEDs DISADVS: more expensive
• Magnetic ink character readers (MICRs) are able to read characters in a special ink
• MICRS ADVS: less chance of human error, characfer cannot be altered and can read even if written over
• MICRS DISADVS: more expensive, limited number of characters can be read
• radio frequency identification (RFID) reads info stored on tags using radio waves
• RFID ADVS: read objects from distance, read in bulk and fast and allows read write operations to take place
• RFID DISADVS: radio symbols can be jammed or hacked, more expensive and tags could interfere with each other